JP2000052293A - Low friction rotary knife - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a burden to a user by engaging a blade and a blade supporting structure with each other along a bearing contact position to be positioned separately in a direction in parallel with a shaft so that the blade is stabilized at both ends in the radial direction and in the axial direction when a knife works. SOLUTION: A blade support structure 16 is supported free to rotate around a central shaft 22 of a blade 12 as its center, and the blade and the blade support structure are devised to be engaged with each other at a bearing position positioned separately in the axial direction. The blade support structure 16 forms a divided ring type structure constituted of a ring curved body part and a fitting part 32. The ring curved body part maintains the blade in a state combined with a knife while supporting the blade so that the blade can stably rotate in low friction and at high speed even when various force is applied on it while the knife works. Consequently, it is possible to minimize friction and heating of the blade at the time when the knife works and to stabilize the position of the blade.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to power-driven rotary knives, and more particularly, to a rotating shaft having a central shaft with a blade support structure that provides bearing contact to reduce blade vibration and heating. The present invention relates to a power-driven rotary knife supported to be able to rotate around.

[0002]

BACKGROUND OF THE INVENTION Powered rotary knives are widely used in meat packaging and other commercial food processing facilities. These knives are usually constituted by a handle and a blade housing that supports an annular knife blade. The knife blade is driven to rotate about its central axis relative to the blade housing by a motor via a gear train.

[0003] The knife blade is formed of an annular body, the blade portion of which protrudes axially from the annular body, and the drive gear tooth portion which protrudes from the annular body on the opposite side of the blade portion in the axial direction. ing. The blade housing holds the blade in position relative to the knife when the blade is rotating. The blade is subjected to various forces by both the power transmission and cutting action of the knife.

[0004] In some knives, the blade housing forms a support surface in the form of a peripheral groove whose cross section is rectangular to receive the blade and gear teeth. These blade housings are often split and can be elastically extended to receive the blades. The blade body and the gear teeth are formed to face axially opposed blade surfaces with a sufficient operating spacing to prevent the blade from being incorporated into the groove. As a result, the blade and the blade housing are each slidably engaged on the large contact surface.

[0005] In some other knives, the blade housing extends radially inward to form a frusto-conical surface that engages the frusto-conical blade surface to prevent the blade from moving axially away from the blade housing. Has a lip. In such instances, these knives have shoes that pivot and engage the blades. These shoes also have a frusto-conical surface that pushes the blade toward the blade housing and holds the blade in place.

Some such conventional rotary knives tend to vibrate during use because the blade rotation axis is displaceable relative to the blade housing. Stated another way, the blades tend to rattle within the blade housing and cause the entire knife to vibrate. In the case of a knife where the blade is fixed to the knife by the facing housing surface, vibration of the blade causes the blade to move axially, resulting in undesirable contact with the blade housing. Such axial movement of the blade can result in both knife vibration and blade heating. In order to cause the blade to rotate about an axis that is relatively fixed with respect to the blade housing, the diameter of the blade housing is defined by the radially outer blade body, the gear surface, and the radially outer race surface. The radial spacing between them is adjusted to be as small as possible. This reduces vibration.

[0007]

Although vibrations are reduced, other problems arise. First, when the blade housing is adjusted to provide a tight working spacing, the heat generated by the frictional contact between the blade and the blade support often alters the trimmed product. In some cases. The heated product creates a sticky build-up on the knife portion, which generates more frictional heat. In some situations, adjusting the diameter of the housing may cause the race to change slightly from a circular or planar shape. These conditions tend to result in vibration and heating.

[0008] A common approach to remedy these problems is to combine the blade and housing with an operating interval that keeps vibration to a tolerable level and avoids overheating. Another approach used to reduce vibration and heating is to operate the knife at the lowest possible speed. The load on the user required to operate the knife increases as the operating speed decreases, as the slicing operation is reduced. Despite these workloads, knives according to the prior art tend to generate vibrations and overheating. When operated at a low speed, the load on the operator increases in addition to vibration and frictional heat.

The present invention supports the blades to rotate about a central axis at a plurality of line contact bearing locations, allowing the knife to operate at relatively high speed with minimal vibration and heating. Thus, there is provided a new and improved annular blade for rotating knives that also reduces the burden on the user.

[0010]

According to a preferred embodiment of the present invention, a power-driven knife includes a blade support structure for rotatably supporting an annular blade about a central blade axis. The blade and the blade support structure are engagable along bearing contact locations that are spaced apart in a direction parallel to the axis such that the blade is stable in both radial and axial directions when the knife is actuated.

The rotating knife blade includes an annular body disposed about a central axis and an annular blade protruding from the annular body. The annular bodies form blade bearing surfaces that become narrower toward each other.

In the preferred knife, the blade support structure has a split blade that can expand and contract radially to receive the blade. The housing member is provided with a rim which is circumferentially spaced around the outer periphery of the blade, protrudes into a bearing race formed on the blade and which engages the blade bearing surface when the knife is actuated. Split blade
The housing member is adjusted so that its blade and housing engage along a relatively short line of bearing contact. The rim located at a distance, when the blade rotates,
The blade is stabilized by a series of bearing positions spaced apart in both the outer circumferential direction and the axial direction of the blade. The axis of rotation of the blade is thus kept essentially in a stationary position with respect to the knife, and the operation of the knife becomes almost vibration-free. Because the blades are lifted by the bearing position, they remain separated except for the bearing position, even if the blade housing undergoes a circular or planar deformation.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A power-driven knife according to a preferred embodiment of the present invention is shown in FIGS. 1 and 2 and comprises a handle 12, a head-piece 14, a blade support structure 16, and an annular blade 20. ing.
Knife 10 extends into handle 12 and is connected to a remote electric motor via a flex shaft 21 that transmits drive from the motor to blade 20.

The motor and flex shaft may be of any conventional or suitable construction and will not be shown or described in detail herein. The flex shaft cuts the meat by the knife user holding the handle,
It suffices to simply and accurately move the knife while shaping or cutting the meat from the bone. The handle 12 and the head-piece 14 may be based on any conventional or suitable structure and will not be described in detail. Although a knife driven by an electric motor is described, the knife includes a compressed air motor in handle 12 and may be connected to a compressed air supply by a suitable hose.

The blade support structure 16 has the blade 12 as a central axis.
The bearing is rotatable about 22 so that the blade and the blade support structure can be engaged at least in axially spaced bearing positions (e.g., spaced apart in the direction of axis 22). . In a preferred embodiment, the bearing position is formed by a circumferential line portion. The bearing line portion ensures that the blade and the blade support structure engage only in a very small contact area. The axially spaced bearing line portions are supported so that the blades can resist transverse and axial vibrations against the blade support structure, while at the same time providing frictional resistance to blade rotation provided by bearing contact. Is to be as small as possible. FIG.
As best shown in FIG. 2, an axially spaced bearing position is one that supports the blade such that the blade and the blade support structure remain apart except in the bearing position.

The illustrated blade support structure 16 has a split ring shape comprising an annular curved portion 30 extending around the blade 20 and an axially extending mounting portion 32 for securing the blade support structure to the head-piece. A structure is formed (see FIGS. 2 to 4). The annular curved portion 30 extends almost completely around the blade, and the split 33 is centered with the head-piece. The attachment portion 32 extends in the axial direction from the annular curved body portion 30 and is detachably connected to the head-piece.

The mounting portion 32 is shown as an annularly curved wall-like structure facing the head-piece, and the split 33 passes through its center. The mounting portion 32 defines an open end mounting slot 34 on each side of the split 33 for receiving mounting screws 36 (FIG. 2) for securing the blade support structure on the head-piece. Slot 34 is significantly wider than the diameter of the thread groove. The mounting screw head 38 is significantly lower than the slot. The screw heads engage the mounting portions 32 on opposite sides of the corresponding mounting slots 34 to secure the blade support structure to the head-piece when the screws are tightened.

The central portion 40 of this mounting portion covers the adjacent head-piece surface, and thus is mounted on the head-piece and covers a blade drive pinion gear 41 (see FIG. 2) driven by the flex shaft 21. The surface of the central portion facing the head-piece is machined to form a plane facing the pinion gear 41, so that the wall thickness of the central portion decreases as approaching the split 33 (see FIG. 3).

[0019] Curved head-piece surface and its central part
The opposing curved mounting surfaces on both sides of 40 form engaging grooves and lands that extend circumferentially with respect to the blade support structure so that the blade support structure is securely aligned and supported with the head-piece. It has become.

The annular curved portion 30 holds the blade in combination with the knife while supporting the blade to enable stable, low friction and high speed rotation even when various forces are applied during operation of the knife. I do. Annular curved section 30 forms an annular groove or space 42 on the groove to receive blade 20 when the blade is assembled to a knife (see FIGS. 7 and 8).

The groove engages the radiator wall 44, the outer peripheral wall 46 extending around the outer periphery of the blade, and the blade 20, partially in a plane extending perpendicular to the blade axis 22. For this purpose, it is formed by a blade retaining bearing structure 46 extending inward from the wall 46. The walls 44, 46 are cut out of any of the splits 33 to provide an annular spacing 48 (FIGS. 3, 4 and 6) for the pinion gear 41.

The blade 20 is constituted by an annular body 50 and an annular blade body 52 arranged around the central axis 22.
In the illustrated embodiment of the invention (FIG. 9), the annular body 50 forms first and second shaft ends 56,58.
The blade portion 52 protrudes from the first shaft end 56 in the axial direction.

The annular body 50 includes a gear tooth 60 defining a second axial end 58 remote from the blade portion 52, and a wall 62 defining a radially outer surface 64 disposed between the ends 56,58. , And face 64
It is formed by an annular bearing race or groove 66 that opens to the outside. The illustrated gear teeth 60 are notched through the wall 62 to form a ring gear extending around the end 58. The gear teeth 60 are located in a blade support structure adjacent to its walls 44, 46 and include a pinion gear and a ring gear.
The gears are engaged in the spacing space 48. The ring gear engages the drive pinion gear 41 when the knife 10 is actuated.

Since the bearing race 66 receives the bearing structure, the blade portion 50 is firmly secured by the engagement along the bearing positions axially spaced between the bearing race and the bearing structure so that the blade is axially in use when in use. And it is designed to be firmly supported so as not to shift in the radial direction. The bearing race 66 extends into the wall 62 and has a surface 64 axially spaced from the blade portion 52 extending between the bearing structure 47 and the blade portion 52.

The bearing races 66 include first and second bearing surfaces 70, 72 that taper toward each other. In the knife shown, the race extends inside the radially inner wall. The bearing surface 70 narrows away from the second shaft end 58, and the second bearing surface 72 narrows as it approaches the first bearing surface 70. In the illustrated blade, the surfaces 70, 72 are frusto-conical. As shown, those surfaces are joined at their radially inner end by another short, axially extending surface 74 that minimizes the depth of the race and prevents it from engaging the bearing structure 47. Have been.

The blade section 52 is based on conventional or suitable construction, and becomes thinner as it moves away from the annular body 50 and closer to each other in the direction of the cutting end of the protruding blade end as shown. Radially inner and outer surfaces 90,
Formed by 92. With the knife shown,
End 94 is formed by the connection of surface 90 with surface 96 extending between surfaces 90 and 92. The surfaces 90, 92 are shown as being continuous with the blade body 50, and as the surfaces 90, 92 become smaller, the wall thickness of the blade portion becomes less than the thickness of the annular body 50.

Although one specific blade configuration is disclosed, various annulus blade configurations are commonly used in power-driven knives depending on the specific use of the knife. Any configuration may be used in the knife embodying the present invention.

In a preferred and illustrated embodiment of the present invention, the blade and the blade support structure are a first plurality of circumferentially spaced apart located in a plane transverse to axis 22. And a second plurality of circumferentially spaced bearing positions located on a second surface extending away from the first surface and extending transversely to shaft 22. Engage along the contacts.

In the knife 10 shown, the bearing structure 47 is circumferentially spaced 3 around the blade support structure.
It is formed by two radially inwardly projecting borders 100. See FIG. 5 and FIGS. Each illustrated rim has a semi-circular cross-sectional shape (see FIG. 9), and each rim has a respective arc-shaped bearing contact line portion 102,1.
Engages firmly with the frustoconical surfaces 70, 72 along 04.
In the knife shown, four edgings 100
a, 100b, 100c, and 100d are formed around the blade support.

By using multiple edgings, when the blade support structure is tightened around the blade,
The spaced-apart rim will engage properly with the blade bearing race. Such a relationship is maintained if the blade support structure deforms out of round or planar shape during the manufacturing process, or if the blade support structure size is improperly adjusted.

With the knife illustrated in FIGS. 1-9, the blade support structure is initially formed with a continuous radially inwardly extending edging. The edgings 100a-100b are formed such that a portion of the initial edging is removed, leaving only the cylindrically curved surface away from the outer periphery of the blade.

The edgings 100a, 100b extend from opposite sides of the split 33 to support the blades against the reaction forces generated by the gears that act to separate the blades 20 from the pinion gear 41 during operation of the knife. . Blade race surface 70
Therefore, the rims 100a, 100 near the pinion gear 41
b. The borders 100a and 100b are the borders 100
Since it is longer compared to c, the reaction load of the gear is distributed over a relatively wide range. Gear reaction load is blade 20
Tends to move away from the pinion gear 41,
The rims 100a, 100b prevent axial blade deflection and maintain bearing engagement with both race bearing surfaces 70, 72. This serves to prevent the circumferential portion of the blade 20 near the pinion gear from shifting axially and radially.
In the blade support structure 16 shown in FIG.
0a and 100b show a similar arc shape of about 58 ° about the axis 22.

The edging portions 100c and 100d are arranged on the diametrically opposite side and away from the head-piece (see FIG. 8). The edgings 100a-100d rest tightly on the surfaces 70, 72 to radially center the blade 20 on the shaft 22 and are secured against axial displacement. Blade rims 100c, 100d when the knife is cutting to separate meat and fat from large animal body parts
The circumferential portion of the blade near the radial blade support
It tends to be pushed in the 44 direction.

The engagement between the bearing surface 72 and the edging portions 100c, 100d eliminates any axial deflection of the blade when cutting or shaping the meat. The radial component of the deflection force is reacted against the edging portions 100a, 100b,
Keep the blade stable in the radial direction. The illustrated rims 100c, 100c respectively
It has a similar arc of about 34 °.

FIGS. 10-14 show an improved knife embodying the present invention. The knives of FIGS. 10 to 14 have the same structure as the knife 10 except for the blade support structure 120 and the blade 122. Therefore, the blade support structure 120 and the blade 1
Only 22 is shown, and only the differences from the blade support structure 16 and the blade 20 will be described in detail. For the remainder of the knife shown in FIGS. 10-14, see FIGS. 1-19 and the associated description. The same blade support structure 120 and blade 1 as the blade support structure 16 and the blade 20
22 is indicated by the corresponding reference numeral.

The blade support structure 120 supports the blade 122 so that the blade 122 can rotate about a central axis 124.
The blade and the blade support structure are adapted to engage at least in bearing positions spaced apart from each other in the direction of the axis 124. An axially spaced bearing position supports the blade such that the blade and blade housing are separated apart from the bearing position (see FIG. 14).

The blade support structure 120 has an outer peripheral wall 130
Are a series of circumferentially spaced radially thick walls
Form 132. The wall portion 132 is substantially aligned on the shaft 124 and forms radially inwardly facing truncated conical bearing surfaces 133 and 134 that become thinner toward the opposite side in the axial direction. These bearing surfaces are engaged by bearing edging surfaces on the blade along the narrow contact tines. In a preferred embodiment, the bearing surfaces 133, 134 form the walls of an inwardly open groove formed in each thicker wall 132. The portion of the outer peripheral wall 130 between these thicker walls is always kept away from the blade edge (FIG. 13).

The blade support structure 120 has bearing surfaces 133 and 134
Can be formed by machining a groove that is opened inward in the radial direction so as to completely surround the inner periphery of the outer peripheral wall 130. Then, thicken the wall 13
0 is formed by processing, and a thin wall portion 135 is provided between the portions 132 (see FIGS. 11 to 13).

The blade support structure shown in FIG. 11 and the like has four thick portions. The two portions 132 extend in opposite directions from the split 33 'of the blade support structure 120. The remaining two thicker portions are diametrically opposite the blade support structure. The bearing surfaces may be distributed in any suitable pattern about axis 124. Further, the number of thick portions may be four or less.

The blade 122 has a bearing race with the blade 20 except that the bearing race of the blade 120 extends continuously around the periphery of the blade and extends radially to form a rimming surface 140 contacting the bearing surfaces 133,134. Is the same. Rim
140 has a semi-circular cross-section and therefore narrows as they approach each other and extends along the entire length of the groove.
A bearing surface is formed along the lines 2 'and 104' to contact the support housing bearing surface.

The blade and the blade support structure engage only along a very small contact surface. The axially spaced bearing contact line portions are supported so that the blade resists radial and axial vibrations against the blade support structure, while at the same time minimizing the frictional resistance acting on the rotation of the blade by the bearing contact. To

The blade support structure 120 contacts the rim 140 and supports the blade so that it does not contact the blade support structure except at the line of bearing contact.
It is tightly tightened around 3,134 (see Fig. 14). When positioned as desired, blade support structure 120 is secured in place by a tightening screw, such as screw 36 or the like.

FIGS. 15 and 16 show a further alternative construction of the knife 10 similar to the knife 10 of FIGS. The blade support structure 160 has six bearing edgings 200a, 200b, 200c, 200 instead of the four bearing edgings provided by the blade supporting structure 16.
d, 200e and 200f are provided to provide bearing contact with the blade, except that
It has the same structure as. The blade used with blade support 160 is exactly the same as blade 20, and therefore need not be described. Parts of the blade support structure 160 that are the same as parts of the blade support structure 16 are given the same reference numerals and will not be described here.

The bearing molecular sieves 200a and 200b have cracks 33.
Especially the blades that extend from both sides of the
The blades are supported against the reaction force generated by the gear that tries to separate 20 from pinion gear 41. Rim
200a and 200b occupy the same arc length as the edging portions 100a and 100b and are longer than the edging portions 200c to 200f, respectively, so that the reaction load of the gear is distributed over a relatively wide range.
The reaction load of the gear tends to displace the blade 20 away from the pinion gear, but the edges 200a, 2
00b prevents axial deflection of the blade and maintains it in bearing engagement with both blade and race bearing surfaces 70,72. The circumferential portion of the blade 20 near the pinion gear is constrained from axial and radial displacement by engagement of the rim with the race. The blade support 160 shown in FIGS.
00a and 200b occupy the same arc of about 58 ° about the axis 22.

The edging portions 200c and 200d are connected to the edging portions 200a and 200d.
On the opposite side to 00b in the radial direction, it is arranged away from the knife head-piece. The rims 200c and 200d are shown in FIGS.
9 and are spaced apart by the same arc length, that is, each occupy an arc length of about 34 ° about the axis 22, and the rim is located about 34 ° apart. ing.

The edging portion 200e is centered between the edging portions 200a and 200b, and the edging portion 200f is
It is centered between b and 200d. See FIG. The borders 200e, 200f each occupy a 35 ° arc. The edging portions 200c to 200f firmly rest on the blade bearing surfaces 70 and 72 to hold the blade 20 in a radially centered position on the shaft 22 so that axial displacement does not occur.

The edgings 200a-200f are in contact with the bearing surfaces 70, 72 and with each other to prevent the blade from vibrating axially or radially. The tendency of one circumferential portion of the blade 20 to flex in the axial direction creates an axial and radial component of the reaction force exerted on the blade by the rim engaging the circumferential blade portion. Otherwise, the radial movement of the blade occurs because the radial force that pulls the blade radially away from the edging is counteracted by one or more edgings located diametrically opposite the blade. Absent. This reduces the vibration of the blade.

Knives with blade support structure 160 exhibit longer effective blade life than those with blade support structure 16. If the edgings 100a-100d wear as a result of prolonged use, the blade 20 may be used in use.
May be in contact with the blade support body 30 in the space between the edges 100b and 100c or between the edges 100b and 100d. Even so, the blades will wear and will eventually need to be replaced. If the knife with the blade support structure 160 experiences similar wear on the edgings 200a-200d, the edging 200e or edging 200f ensures that the blade 20 never contacts the portion 30 and therefore Blade wear can be avoided. It has been observed that the amount of heat generated by the blade support structure 160 is not greater than the heat generated by the blade support structure 16.

The borders 100, 200 shown in connection with FIGS. 1-9 and FIGS. 15, 16 are respectively symmetrical about a line 202 extending through the split 33 and diametrically opposed to the blade support 30. Located on the side. In addition, the edging portions 100a to 100d or the edging portions 200a to 200f may be dispersedly arranged in different configurations around the portion 30, or may have different arc lengths depending on the purpose of use of the knife. Furthermore, depending on the intended use of the knife,
The number of edging portions may be three, five, or six or more.

Theoretically, if the blade 20 is supported at a bearing location that is axially remote and substantially surrounds its outer circumference, then even one edge extending around the blade 20 can be a knife 10. Could be used in In practice, such a structure is problematic because the blade support structure must be able to expand radially to allow for removal and replacement of the blade. It is difficult to adjust the diameter of the blade support structure so that the blade is evenly and securely engaged with its outer periphery by one edge. The blades tend to engage at one or two random locations, causing radial and axial vibration. In addition, when the blade is firmly engaged by the blade support structure about its entire circumference, a single edging will result in a longer length bearing surface
Since the blades 70 and 72 come into contact with each other, the heat generated by the blade during use is larger than that of the blade having a plurality of bearing rims.

While various embodiments of the present invention have been shown and described above, the present invention is not limited to these structures. Various modifications, adaptations, and uses of the present invention will readily occur to those skilled in the field of powered rotary knives. It is intended that the appended claims and their modifications, applications and uses consistent with their spirit be included in the present invention.

Other features and advantages of the present invention will become apparent from the description of a preferred embodiment and with reference to the drawings, which form a part of this specification.

[0053]

The present invention is as described above and includes a split blade housing member which can be expanded and contracted radially to receive a blade,
The split blade housing and blade engage along a relatively short line of bearing contact which helps to minimize friction and blade heat when the knife is actuated, and the bearing position is defined by the circumferential direction of the blade and the axis. Being spaced apart in both directions has the effect that the position of the blade is stabilized during operation of the knife.

[Brief description of the drawings]

FIG. 1 is a plan view of a power-driven knife incorporating a blade according to the present invention.

FIG. 2 is an elevational view showing a section of FIG. 1 in section.

FIG. 3 is an overhead view of a blade support structure forming part of the knife of FIGS. 1 and 2;

4 is an elevational view taken generally from the plane indicated by line 4-4 in FIG. 3;

FIG. 5 is a view taken substantially from the plane indicated by line 5-5 in FIG. 4;

6 is a sectional view taken generally from the plane indicated by line 6-6 in FIG. 5;

FIG. 7 is a partially enlarged view of a part of the blade support structure of FIG. 6;

FIG. 8 is a cross-sectional view taken generally from the plane indicated by line 4-4 in FIG.

FIG. 9 is an enlarged partial cross-sectional view of a portion of the knife shown in FIG. 1 taken generally from the plane indicated by line 9-9 in FIG.

FIG. 10 shows an improved knife embodying the present invention.
FIG.

FIG. 11 is an enlarged cross-sectional view of a portion of the blade support structure of FIG. 10 as viewed substantially from the plane indicated by line 11-11.

FIG. 12 is an enlarged cross-sectional view of a portion of the blade support structure of FIG. 10 viewed from a plane generally indicated by line 12-12.

FIG. 13 is an enlarged cross-sectional view of a portion of the blade support structure of FIG. 10 as viewed substantially from the plane indicated by line 13;

FIG. 14 is an enlarged partial sectional view similar to FIG. 9 of the improved knife with the blade assembled to the blade support.

FIG. 15 is an overhead view of a portion of another improved knife embodying the present invention.

16 is a cross-sectional view taken generally from the plane indicated by line 16-16 in FIG.

Claims (23)

[Claims] The blade support structure includes a handle, a headpiece, a blade support structure, and an annular blade member supported by the blade support structure for rotation about a central axis, the blade support structure being substantially continuous about the blade member. It is constituted by a blade support member extending to
A powered knife wherein the blade member and the blade support member are engageable in at least three bearing positions spaced about the central axis. 2. The blade support member is divided by a split disposed on a head-piece, and one of the bearing positions is divided.
A powered knife according to claim 1, wherein one is located on one side of the split and the second bearing position is located on the opposite side of the split. 3. The power-operated knife of claim 1, wherein the blade bearing is split and made of a hard, resistive material, and the split allows for adjustment of the diameter size of the blade bearing. 4. The power driven knife according to claim 1, wherein the bearing position is determined by a protrusion on a blade bearing member extending over the blade. 5. A powered knife according to claim 1, wherein the bearing position is defined by a surface on the blade extending in the direction of the blade support. 6. An annular body which forms first and second shaft ends and is disposed around a central axis, and an annular blade portion projecting axially from the first shaft end of the annular body. A wall configured to define a radially outer surface disposed between the first and second shaft ends; and an annular bearing race provided on the surface and extending into the radial wall. A first groove surface that is gradually narrowed from the second shaft end, and a first groove surface that is gradually narrowed in the direction of the first groove surface. A rotating knife blade comprising two groove surfaces, the first and second groove surfaces forming first and second surfaces separated axially. 7. The rotating knife blade according to claim 6, wherein at least one of the surfaces is frustoconical. 8. The rotating knife blade according to claim 7, wherein both of the bearing surfaces are frusto-conical. 9. The rotating knife blade according to claim 6, wherein the annular body wall is generally cylindrical. 10. The knife blade according to claim 6, wherein the first shaft end of the conventional device is disposed close to the blade portion. 11. The knife blade according to claim 7, including a third groove wall surface extending between adjacent ends of the bearing surface. 12. The knife blade according to claim 8, wherein the cone angles of the first and second bearing surfaces are substantially the same. 13. A blade support structure and an annular blade supported by the blade support structure for rotation about a central axis, wherein the blade and the blade support structure are arranged in a plane transverse to the axis. A power-driven knife engagable with the bearing contact in a direction parallel to the axis along a line of the bearing contact and engagable with a second line of the bearing contact located away from the first line. 14. The first and second lines of the bearing contact are formed in part by an edge on one of the blades or the blade support structure, the edge engaging with the other of the blade or the blade support structure. And the line of bearing contacts is formed in part by a spaced bearing surface formed on the other of the blade or blade support structure, the bearing surface being engageable with the rim. 14. The knife according to claim 13. 15. The knife according to claim 14, wherein a bearing surface is formed on the blade. 16. The bearing contact lines are of a first plurality of bearing positions, are circumferentially spaced about an axis, and the second bearing contacts are of a second plurality of bearing positions. 14. The knife according to claim 13, wherein the knife is arranged circumferentially away from the axis. 17. Each of the first and second plurality of bearing locations is formed, in part, by a series of circumferentially spaced edgings on the blade or blade support structure, the edgings being blades. Alternatively, the bearing portion protrudes in the direction of the engaging portion with the other of the blade support structures, and the bearing position is partially constituted by a blade or a bearing surface that is located away from the other of the blade support structures, and the bearing surface is bordered 17. The knife according to claim 16, engagable with a section. 18. A blade support member, which extends substantially continuously around a central axis and is bent and divided into an annular shape, wherein the blade support member forms first and second plurality of bearing positions. The bearing positions of the first plurality of bearing positions are circumferentially separated from each other around the axis, and the bearing positions of the second plurality of bearing positions are circumferentially around the axis. Are separated from each other in the direction
The support structure for an annular knife, wherein each of the plurality of bearing positions is axially separated from each of the second plurality of bearing positions. 19. The support structure according to claim 18, wherein the first and second plurality of bearing positions are formed by bearing rims extending radially inward from the blade support member. 20. The support structure according to claim 18, wherein the first and second plurality of bearing positions are formed by bearing surfaces opened radially inward of the support structure. 21. A bearing position extending circumferentially about a central axis, a first bearing position forming a bearing contact line at least in a plane transverse to the axis, and at least a first contact line. A second bearing position defining an axially spaced second bearing contact line, the blade support structure for a rotatable annular knife blade. 22. The blade support structure according to claim 21, wherein the first and second bearing contact lines are formed by bearing rims projecting radially inward from the blade support structure. 23. The blade support structure according to claim 21, wherein the bearing contact line is formed by a plurality of edges projecting radially from the blade support structure.